The monthly target set by seven core OPEC+ members is expected to be raised by about 188,000 barrels per day, the sources said.
All spoke on condition of anonymity and said a final decision had not been made.
OPEC+ held output steady in the first quarter of 2026 but has raised its target each month since April, despite the war.
The size of the monthly hikes has been trimmed since May after United Arab Emirates left the group.
Its departure decreases the group’s power over the market but may boost its internal cohesion, according to analysts and delegates.
OPEC, Saudi and Russian officials did not immediately reply to Reuters’ requests for comment.
OPEC+ oil production dropped to 33.19 million bpd in April from 42.77 million in February, OPEC figures show.
Output by Gulf producers fell by 9.9 million bpd.
One significant impact of the war is that among the exporters impacted are the group’s only ones with spare capacity to pump more if needed – Saudi Arabia, Iraq and Kuwait, and until recently, the UAE.
The seven of 21 OPEC+ members due to meet are Saudi Arabia, Iraq, Kuwait, Algeria, Kazakhstan, Russia, and Oman.
Two other OPEC+ meetings also scheduled for June 7 are not expected to make any policy changes, the sources said.
A separate, group-wide output cut of 2 million bpd agreed in 2022 is scheduled to remain in place until the end of 2026, though that included a cut of 160,000 bpd apportioned to the now-departed UAE.